Re: [PATCH] powerpc/smp: Expose die_id and die_cpumask
From: Shrikanth Hegde <hidden>
Date: 2025-11-10 17:03:23
Also in:
lkml
Without this change.
$ grep . /sys/devices/system/cpu/cpu8/topology/{die*,package*} 2> /dev/null
/sys/devices/system/cpu/cpu8/topology/package_cpus:0000,ffffff00
/sys/devices/system/cpu/cpu8/topology/package_cpus_list:8-31
With this change.
$ grep . /sys/devices/system/cpu/cpu8/topology/{die*,package*} 2> /dev/null
/sys/devices/system/cpu/cpu8/topology/die_cpus:0000,0000ff00
/sys/devices/system/cpu/cpu8/topology/die_cpus_list:8-15
/sys/devices/system/cpu/cpu8/topology/die_id:4
/sys/devices/system/cpu/cpu8/topology/package_cpus:0000,ffffff00
/sys/devices/system/cpu/cpu8/topology/package_cpus_list:8-31
snipped lstopo-no-graphics o/p
Group0 L#0
Package L#1
NUMANode L#1 (P#2 8135MB)
Die L#0 + Core L#1Die L#0 -> Here L# indicates logical die number. One should run --verbose to see theactual die_id. For example: Die L#8 (P#25) --> die_id is 25. Maybe you could the same CPU's (CPU8) info of lstopo here?
L3 L#2 (4096KB) + L2 L#2 (1024KB) + L1d L#2 (32KB) + L1i L#2 (48KB)
PU L#8 (P#8)quoted hunk ↗ jump to hunk
Signed-off-by: Srikar Dronamraju <redacted> --- arch/powerpc/include/asm/topology.h | 4 ++++ arch/powerpc/kernel/smp.c | 18 ++++++++++++++++++ 2 files changed, 22 insertions(+)diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h index f19ca44512d1..c6ad1eb7e44a 100644 --- a/arch/powerpc/include/asm/topology.h +++ b/arch/powerpc/include/asm/topology.h@@ -132,6 +132,8 @@ static inline int cpu_to_coregroup_id(int cpu) #include <asm/cputable.h> struct cpumask *cpu_coregroup_mask(int cpu); +const struct cpumask *cpu_die_mask(int cpu); +int cpu_die_id(int cpu); #ifdef CONFIG_PPC64 #include <asm/smp.h>@@ -141,6 +143,8 @@ struct cpumask *cpu_coregroup_mask(int cpu); #define topology_sibling_cpumask(cpu) (per_cpu(cpu_sibling_map, cpu)) #define topology_core_cpumask(cpu) (per_cpu(cpu_core_map, cpu)) #define topology_core_id(cpu) (cpu_to_core_id(cpu)) +#define topology_die_id(cpu) (cpu_die_id(cpu)) +#define topology_die_cpumask(cpu) (cpu_die_mask(cpu))
nit: can we fix the tab spacing here please? Maybe like below? +#define topology_sibling_cpumask(cpu) (per_cpu(cpu_sibling_map, cpu)) +#define topology_core_cpumask(cpu) (per_cpu(cpu_core_map, cpu)) +#define topology_core_id(cpu) (cpu_to_core_id(cpu)) +#define topology_die_id(cpu) (cpu_die_id(cpu)) +#define topology_die_cpumask(cpu) (cpu_die_mask(cpu))
quoted hunk ↗ jump to hunk
#endif #endifdiff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 68edb66c2964..a0b0b46b78e3 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c@@ -1085,6 +1085,24 @@ static int __init init_big_cores(void) return 0; }
As you have mentioned in the changelog, could you add a comment here explaining on which systems we see this information correctly.
+const struct cpumask *cpu_die_mask(int cpu)
+{
+ if (has_coregroup_support())
+ return per_cpu(cpu_coregroup_map, cpu);
+ else
+ return cpu_node_mask(cpu);
+}
+EXPORT_SYMBOL_GPL(cpu_die_mask);
+
+int cpu_die_id(int cpu)
+{
+ if (has_coregroup_support())
+ return cpu_to_coregroup_id(cpu);
+ else
+ return -1;
+}
+EXPORT_SYMBOL_GPL(cpu_die_id);
+
void __init smp_prepare_cpus(unsigned int max_cpus)
{
unsigned int cpu, num_threads;Other than above: Reviewed-by: Shrikanth Hegde <redacted>